Effects of Organic Based Heat Stabilizer on Properties of Polyvinyl Chloride for Pipe Applications: A Comparative Study with Pb and CaZn Systems

Abstract

In this paper, the effects of organic based stabilizers (OBS) are investigated and compared with traditional lead (Pb) and calcium zinc (CaZn) heat stabilizers regarding their processability, mechanical property, and thermal degradation behaviors in rigid PVC pipe applications. In addition, the effects of repeated processing cycles on the degree of gelation and the impact strength of the PVC/OBS, PVC/CaZn, and PVC/Pb are also examined. A repeated processing cycle of those three types of the heat stabilizers up to four cycles was found to increase the degree of gelation and proved no significant effect on the impact strength and heat resistance of the resulting PVC samples. The OBS showed a positive effect on preventing the autocatalytic-typed thermal degradation of the PVC samples. This leads to a longer retention time for the initial color change of the PVC/OBS compared to PVC/Pb or PVC/CaZn systems. This characteristic was related to a more uniform fusion behavior of the PVC/OBS, i.e., the lowest gelation speed and the longest fusion time. The non-isothermal kinetic parameter determined by the Kissinger and Flynn–Wall–Ozawa methods of the dehydrochlorination stage of the PVC/OBS was in satisfactory agreement and continued to compare with the PVC/Pb and PVC/CaZn systems. The results indicated that the OBS might decrease the dehydrochlorination rate of PVC, implying that PVC/OBS was more stable than PVC/Pb and PVC/CaZn systems.

Poly Vinyl Chloride Additives and Applications-A Review

“…The most common heat stabilizers are metal salts, soaps. Table 3 shows heat stabilizers types [24,25].…”

“…DBL phosphate is a light stabilizer that has some UV resistance properties. Light stabilizers are complex chemicals, very expensive, and are efficient at low amount (0.1-0.3 PHR) [24].…”

The Influence of NBR Waste Modified with SiO2/Not Modified on Processability, Physical-Mechanical and Structural Properties of PVC

“…Moreover, for the same weight of the batch, the volume of the mixture containing NBR waste is higher than that of PVC, which results in a higher shear effort. Due to these effects, the gelling of mixtures containing PVC/NBR waste functionalized/ unfunctionalized is faster than that of PVC (Bendjaouahdou and Aidaoui, 2021;Jubsilp et al, 2022;Mirowski et al, 2021).…”

Thermal stabilization of polyvinyl chloride by calcium and zinc carboxylates derived from byproduct of palm oil refining

“…Pipes and fittings accounted for a major application share by volume and value, followed by profiles, hoses, and tubing (Mordor Intelligence, 2022). However, PVC is thermally unstable at processing temperatures (Jubsilp et al, 2021). Its poor thermal stability is the biggest weakness of PVC (Li et al, 2019).…”

“…The compounds used as thermal stabilizers can be divided into two groups: metal-free organic and metal-based groups ( Folarin and Sadiku, 2011 ; Schiller, 2015 ). The first group is relatively new technology ( Jubsilp et al., 2021 ). The disadvantage of organic thermal stabilizers are their poor stability ( Guangbao et al., 2020 ).…”